On Friday 10 October 2014 12:15:34 Jon Elson did opine And Gene did reply: > On 10/10/2014 09:45 AM, p...@wpnet.us wrote: > > If you can TDR from both ends of the cable, knowing the exact VP > > doesn't matter. The fault will be in the middle between the two > > readings. I've used this to find faults in twisted pair audio cable > > using a coax TDR. > > Also, if the far end is not terminated, or offers enough > discontinuity to show up > on the TDR trace, you can measure the whole length of the > line and compute > how far down the fault is. > > Jon
That could be used IF the endpoint was a bad match, but in terms of a TDR, if its a 6 bay superturnstile antenna that is actually well matched at its normal operating frequency, is such a mess on the TDR screen as to render it worthless. If you know the exact footage to the splitter at the center of the antenna, then one could use that bump as a known distance, then ratio the thing to where the fault is. So basically, that cat is going to be skinned regardless. Unforch, the normal fault fail when there is 20+ kilowatts of synch tip power available to really burn things up, it winds up being a short, or an open, so nothing beyond the problem will be seen on the screen anyway. Once the fire is started, unless the transmitter sees the fault and shuts itself off, it isn't unusual for the fire, which crawls toward the power src at a fairly high rate of speed, to burn up stuff from the original failure point all the way back to the 4KM100LA's output cavity, and its the arc detector watching the cavity that actually initiates the take down sequence. But at that point you may be pulling 1000 feet of 6.125" 75 ohm line down, cleaning and replacing burnt teflon as you go. Usually thats a 3 to 5 day job depending on how far away the teflon stuff is and whether the local lumber yard/paint store has enough alcohol to get it cleaned up. If you can find a couple 55 gallon drums thats a good start. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS ------------------------------------------------------------------------------ Meet PCI DSS 3.0 Compliance Requirements with EventLog Analyzer Achieve PCI DSS 3.0 Compliant Status with Out-of-the-box PCI DSS Reports Are you Audit-Ready for PCI DSS 3.0 Compliance? Download White paper Comply to PCI DSS 3.0 Requirement 10 and 11.5 with EventLog Analyzer http://p.sf.net/sfu/Zoho _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
